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| author | David S. Miller <davem@davemloft.net> | 2018-01-15 14:53:44 -0500 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2018-01-15 14:53:44 -0500 |
| commit | db9ca5cacbda79c3c51c723006418f5b864b47fe (patch) | |
| tree | 84e0e11399bdb5eb0f479497026f16d5a7259a8f /net/ipv4/arp.c | |
| parent | 17d0fb0caa68f2bfd8aaa8125ff15abebfbfa1d7 (diff) | |
| parent | cd9ff4de0107c65d69d02253bb25d6db93c3dbc1 (diff) | |
Merge branch 'ipv4-Make-neigh-lookup-keys-for-loopback-point-to-point-devices-be-INADDR_ANY'
Jim Westfall says:
====================
ipv4: Make neigh lookup keys for loopback/point-to-point devices be INADDR_ANY
This used to be the previous behavior in older kernels but became broken in
a263b3093641f (ipv4: Make neigh lookups directly in output packet path)
and then later removed because it was broken in 0bb4087cbec0 (ipv4: Fix neigh
lookup keying over loopback/point-to-point devices)
Not having this results in there being an arp entry for every remote ip
address that the device talks to. Given a fairly active device it can
cause the arp table to become huge and/or having to add/purge large number
of entires to keep within table size thresholds.
$ ip -4 neigh show nud noarp | grep tun | wc -l
55850
$ lnstat -k arp_cache:entries,arp_cache:allocs,arp_cache:destroys -c 10
arp_cach|arp_cach|arp_cach|
entries| allocs|destroys|
81493|620166816|620126069|
101867| 10186| 0|
113854| 5993| 0|
118773| 2459| 0|
27937| 18579| 63998|
39256| 5659| 0|
56231| 8487| 0|
65602| 4685| 0|
79697| 7047| 0|
90733| 5517| 0|
v2:
- fixes coding style issues
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/arp.c')
| -rw-r--r-- | net/ipv4/arp.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index a8d7c5a9fb05..6c231b43974d 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -223,11 +223,16 @@ static bool arp_key_eq(const struct neighbour *neigh, const void *pkey) static int arp_constructor(struct neighbour *neigh) { - __be32 addr = *(__be32 *)neigh->primary_key; + __be32 addr; struct net_device *dev = neigh->dev; struct in_device *in_dev; struct neigh_parms *parms; + u32 inaddr_any = INADDR_ANY; + if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT)) + memcpy(neigh->primary_key, &inaddr_any, arp_tbl.key_len); + + addr = *(__be32 *)neigh->primary_key; rcu_read_lock(); in_dev = __in_dev_get_rcu(dev); if (!in_dev) { |